chore(deps): update nginx docker tag to v1.31.8 (#23)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| nginx | patch | `1.31.6` -> `1.31.8` |

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Reviewed-on: #23
Reviewed-by: stevensting <156+stevensting@noreply.git.coopcloud.tech>
Co-authored-by: Renovate Bot <renovate@coopcloud.tech>

compose.yml

@@ -3,7 +3,7 @@ version: "3.8"
 
 services:
   web:
-    image: "nginx:1.31.6"
+    image: "nginx:1.31.8"
     environment:
       - STACK_NAME
       - DOMAIN=${DOMAIN}